Arrangement for location and rotation of workpieces

ABSTRACT

An arrangement to locate and rotate workpieces with a plane location face and a locating surface of rotation, used mainly for the machining of such workpieces and comprising a drive with a workpiece dog, supporting means, and force elements pressing the workpiece against the supporting means and the dog, wherein the supporting means constitute a combination of two stationary radial supports spaced apart to carry the workpiece surface of rotation, and at least one stationary axial abutment determining the position of the workpiece face. The workpiece dog is capable of self-alignment against the workpiece face, and the force elements are arranged so as to press the workpiece face against the axial abutment with a force less than that of the dog pressure against the workpiece.

United States Patent [72] Inventors Viktor Fedorovieh Khrolenko Zvezdnaya ul., [8, kv. 110; Askold lvaaovich Net'edov, Kolomyali, 2 Nikitinskaya ul. 8, kv. 5; losif Davydovich Gebel, Svetlanovsky prospekt, 35, kv. 54; Arkady Alexandrovich Zykov, prospekt Smirnova, l5, kv. 5.; Jury Viktorovich Kargin, ulitsn Smirnova 10a, kv. 2]; Sergei Sergeevich Konovalov, ulitsa Smolyachkova l3 kv. l6; Viktor lvanovich Parshikov, prospekt K. Marx 70, Irv. 93, all of Leningrad, U.S.S.R. [211 App]. No. 858,387 [22] Filed Sept. 16, 1969 [45] Patented Sept. 14, 1971 [54] ARRANGEMENT FOR LOCATIONAND ROTATION OF WORKPIECES 10 Claims, 9 Drawing Figs.

[52] U.S.Cl 51/237 [5 1] Int. Cl B24b 5/02 [50] Field of Search 51/236, 237; 82/40 Primary ExaminerHarold D. Whitehead AttorneyWaters, Roditi, Schwartz & Nissen ABSTRACT: An arrangement to locate and rotate workpieces with a plane location face and a locating surface of rotation,

used mainly for the machining of such workpieces and comprising a drive with a workpiece dog, supporting means, and force elements pressing the workpiece against the supporting means and the dog, wherein the supporting means constitute a combination of two stationary radial supports spaced apart to carry the workpiece surface of rotation, and at least one stationary axial abutment determining the position of the workpiece face. The workpiece dog is capable of self-alignment against the workpiece face, and the force elements are arranged so as to press the workpiece face against the axial abutment with a force less than that of the dog pressure against the workpiece.

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ARRANGEMENT FOR LOCATION AND ROTATION OF WORKPIECES The present invention relates to apparatus for the location and rotation of workpieces having an external or internal location surface of rotation and a plane-locating face, which apparatus is mainly used in centerless machining of such workpieces..This invention can be employed, for example, in centerless grinding of articles of ring or disk type, and it is of particular interest for the machining of rolling bearing races of very high degrees of accuracy.

Used at present for centerless grinding of articles of said type are various means of location and rotation.

Some of these locate the workpiece from a fixed-plane axial abutment, and from combined radial supports, one of which is immovable, and two others rotate serving as friction disks. The workpiece is rotated and pressed against the fixed axial and radial supports by the friction disks.

The accuracy of work with such locating means is limited due to the radial and axial beat of the friction disks, and the uneven wear of the disks in diameter.

The indicated shortcomings limit the employment of these prior art devices for the machining of counter races of high and very high accuracy.

Also known in the art are other arrangements, wherein the workpiece is located from two fixed radial supports and a rotating axial abutment serving at the same time as the work rotation drive. In such arrangements the workpiece may be pressed against the axial abutment with the aid of a magnetic chuck, pressure rollers or other means.

Along with certain advantages this means of location has a serious disadvantage, namely the beat of the live axial abutment which is transmitted to the workpiece, thus reducing the accuracy of its machining. This is why such a locating device requires the mounting of headstock spindle, wherein the rotating axial abutment is fixed, in precision bearings.

When grinding the raceways of thrust bearings with a tolerance for the raceway nonparallelism relative to the location face being within 0.001 mm., the axial beat of the spindle should not exceed 0.0005 mm. Such an accuracy is achieved through a templet finish of the support shoulder of the spindle and of the axial bearing in the mandrel stock, i.e. by an extremely expensive and laborious operation. Besides, the spindle axial bearing is worn with time, which reduces the accuracy of machining. Thus, the described means of work location and rotation do not ensure the stable work machining at high accuracy.

In accordance with all said above, the object of the present invention is the movable provide apparatus for the location and rotation of ring or disk-shaped articles, which will ensure higher accuracy of work machining as compared with prior art arrangements, and will be equally suitable to machine both outer and inner work surfaces of rotation, as well as the face surfaces thereof.

Another object of the invention is that the apparatus be simple in design, and highly reliable and stable in operation.

To achieve the indicated and other objects, a task was set to change in the work locating and rotating arrangement the system of work support at the time of machining, and the work interaction with its drive.

To solve this task, in the apparatus according to the present invention the supporting means is constructed as a combination of two stationary radial supports spaced apart to carry the work surface of rotation and at least one axial stationary abutment determining the position of the work face, the work dog being capable of self-alignment against the work face, and the force elements being arranged so as to press the work face against the axial abutment with a force less than that of the dog pressure against the work.

The apparatus may have one stationary axial abutment to support the work opposite the zone of its contact with the working tool, the work dog being linearly movable to permit its self-alignment along the axis of work rotation.

The apparatus may also have three axial abutments to support the work at points'not lying in one straight line.

The axial abutments may contact the outer zone of the work-locating surface or they may be mounted in a fixed mandrel passing along the dog rotation axis.

Both the axial and the radial supports can be mounted on a common bar mandrel.

The force elements, which are according to the invention intended to provide different forces of interaction of the work with the axial support and the dog, comprise a magnetic chuck with a magnetic dog capable of self-alignment against the work face.

The magnetic dog may have two plane parallel faces, one of which, adjacent to the part of the magnetic chuck interacting with the dog, in its surface area exceeds by an order of magnitude the other face adjacent to the work, which ensures said difference in the pressure forces.

The apparatus may also be featured by force elements combined with a magnetic chuck providing for magnetic interaction of the dog with the work, which elements comprise springy members to press the work against the axial abutment.

The springy member may be made, for instance, in the form of an annular elastic diaphragm connecting the dog with the drive.

The described improvements eliminate the errors of machining which are due to inaccurate work location, errors in the drive chain, and the beat of the supports.

The invention is further exemplified by the description of embodiments thereof and the accompanied drawings, wherein:

FIGS. 1 and 2 diagrammatically illustrate, in side elevation and plan respectively, the grinding machine, wherein the proposed work locating and rotating arrangement can be employed;

FIG. 3 is an axial sectional view of the work locating and rotating arrangement;

FIG. 4 is a front view thereof;

FIG. 5 is a sectional view of an embodiment of this arrangement with one axial support disposed opposite the working tool;

FIG. 6 is a sectional view which shows an arrangement with three axial supports disposed on the outside of the dog;

FIG. 7 is a sectional view of an arrangement with an elastic diaphragm;

FIG. 8 is an enlarged part of the arrangement shown in FIG. 7; and

FIG. 9 is a sectional view of an embodiment of the locating arrangement, intended for internal grinding.

The work locating and rotating arrangement can be employed in a grinding machine which comprises bed 1 (FIGS. 1 and 2), mandrel stock 2 with drive 3 rotating workpiece 4, and a wheel stand 5 with a drive 6 to rotate a tool 7 which in the present case is a grinding wheel. The drive 3 rotation includes electric motor 8, belt transmission 9 and spindle 10. Drive 6 of the grinding wheel comprises an electric motor 11, a belt transmission I2, and an arbor 13.

The work locating and rotating arrangement comprises two stationary radial supports 14 (FIGS. 3 and 4), whose profile in their working part corresponds to the profile of the cylindrical location surface 15 of workpiece 4 (hereafter termed work," and stationary axial abutments 16, the number of which in this version is preferably chosen to be three. The axial abutments 16 are disposed along a circumference, whose center lies on the axis of rotation of work 4, the machining surfaces of said abutments lying in a common plane perpendicular to the axis of rotation of the work, and fixing the position of the location face 17 of work 4 during the machining process. The width of the axial abutments I6 in the radial direction is less than the width of the job location face 17, therefore they interact with only a part of the location face 17, another part thereof interacting with the face of dog 18 of drive 3 rotating the work. Said two parts of the location face 17 constitute concentric annular zones. Dog I8 is made so that it is capable of a free self-alignment against the location face I7 of work 4. The arrangement must be provided with force elements to press the location face 17 of work 4 against the axial abutments l6 and the dog 18 (these elements are not shown in the drawing). To press the cylindrical location surface 15 of work 4 against the radial supports 14, for example, a permanent magnet 19 can be used. Tool 7 contacts the work.

Work 4 is placed on the stationary radial supports 14 so that its location face 17 is thrust against the face of dog 18. The force elements press the location face 17 against the axial abutments 16, the face of dog 18 being pressed against the work with a force greater than that of the pressure of the work on the axial abutments 16.

The work is pressed against the radial supports 14 on account of its eccentric position with respect to the drive axis, or in some other way, for instance, by means of magnet 19.

The work is brought into rotation by the forces of friction developed between the location face 17 of work 4 and the face of the rotating dog 18. Following is a more detailed description of some of the particular modifications of the proposed arrangement.

The embodiment presented in FIG. is intended to operate on the face surface of the work for instance, to machine raceways in thrust-bearing races.

In this embodiment the outer surface of work 4 is mounted on two fixed radial supports 20, while the locating face surface 17 thrusts against one fixed axial support 21 fitted in the end of a rigid bar 22 mounted on the machine frame. The face surface 23 of work 4 is machined in the zone located opposite the axial abutment 21.

The work rotation drive includes a hollow spindle 25 mounted in mandrel stock 24, pulley 26 being fixed on the rear end of said spindle to transmit thereto the torque from the motor, and the front end of said spindle carrying a movable part 27 of a magnetic chuck, which part is rigidly attached by screws 28 to a magnetic dog 29.

The torque is transmitted from spindle 25 to the movable part 27 of the magnetic chuck by way of elements allowing axial displacement of the movable part 27 with respect to spindle 25, for instance, by a guide key 30.

Dog 29 and the magnetic chuck movable part 27 consist of two annular parts separated from each other by a nonmagnetic liner. The immovable part of the magnetic chuck is made as an electromagnetic coupling 31 and is in rigid connection with the mandrel stock 24 and separated from the movable part 27 with an airgap.

Pressure contact of work 4 with the radial supports is obtained by displacing the centerline of work 4 towards these supports with respect to the axis of rotation of dog 29.

The force elements to press work 4 against the axial abutment 21 comprise compression springs 32 mounted parallel to the centerline of spindle between the movable part 27 of the magnetic chuck and ring 33 fixed on spindle 25. The force of springs 32 is adjusted by a screw 34 which is mounted in the movable part 27 of the magnetic chuck and thrusts against the shoulder of spindle 25. In the initial position, when the chuck is turned off, the axial abutment 21 extends 0.08-0.12 mm. beyond the face of dog 29 (this extension is controlled by the adjustment screw 34).

workpiece 4 is mounted on the radial supports 20 so that its face 17 should thrust against the axial support 21, a clearance remaining between face 17 of workpiece 4 and the face of dog 29.

When coupling 31 is energized, the magnetic lines of force passing through the movable part 27 of the magnetic chuck, and dog 29, are closed through work 4.

Under the effect of magnetic attraction, the movable part 27 together with dog 29 moves axially towards workpiece 4 against the resistance of springs 32, until the face of dog 29 contacts face 17 of workpiece 4. The force between workpiece 4 and the axial support 21 equaling the elastic force in springs 32, should be materially less than the magnetic forces which press workpiece 4 against dog 29.

When spindle 25 rotates, the torque is transmitted therefrom through key 30 to the magnetic chuck movable part 27 with dog 29, and further to workpiece 4.

The distance between the rigid axial abutment 21 and the cutting tool 7 does not depend on the axial beat of spindle 25, nor on the end play of the magnetic chuck, which excludes nonparallelism of surface 23 and the location face 17 during operation. 7

g The end play of dog 29 is balanced by the oscillatory movement of the movable part 27 of the magnetic chuck under the effect of springs 32 and the axial abutment 21.

The axial beat of spindle 25 cannot separate workpiece 4 from the axial abutment 21, as the spindle has no rigid axial connection with dog 29.

The arrangement can be used to machine the face or the inside surface of the workpiece. in this case it has three axial supports 35 (FIG. 6), one of which is placed opposite the too if the face of workpiece 4 is to be machined. Unlike the version according to FIG. 3, the fixed axial abutments 35 interact with the outer part (zone) of the locating face surface of workpiece 4, while dog 36 contacts the inner part thereof. Therefore spindle 37 can be solid, and not hollow like in the arrangement shown in FIG. 5. Dog 36 is connected to the movable part of the magnetic chuck by a hinge.

Serving as the hinge is a ball 38, placed between dog 36 and a cup 39 which is rigidly connected with the movable part 40 of the magnetic chuck by screws 41. In this version of the arrangement the adjustment screw 42 is placed in cup 39 and thrust against the face of spindle 37 (when the magnetic chuck is inactive).

Dog 36 can turn about ball 38, and is thus capable of selfalignment against the location face 17 of workpiece 4 whose position is strictly defined by the three axial abutments 35 and two radial supports 43.

The embodiment shown in FIGS. 7 and 8 is intended for the machining of the face or the outer surface of the workpiece around the hole therein.

Bush 44 carrying two radial supports 45, and cup 46 mounting three axial supports 47, are fixed on bar 48 which, as in the arrangement according to FIG. 3, is jointed to the machine frame. in this version of the arrangement, the functions of the spindle are performed by the magnetic movable part 49 mounted by means of bearings 50 on sleeve 51 made of nonmagnetic material, which sleeve is rigidly connected with bar 48.

The movable part 49 of the magnet chuck is through into rotation by belt 52 connected with the electric motor. in this embodiment of the arrangement, the magnetic chuck is employed to press workpiece 4 not only against dog 53, but against the axial abutments 47 and radial supports 45 as well. This is achieved due to the fact that part F of the magnetic flux F generated by the energized coupling 54, passes through workpiece 4 and is closed through cup 46 with the axial abutments 47, thus forming the force of workpiece pressure against the axial supports, while the remaining part F of the magnetic flux F closes through bushing 44 with the radial supports 45. It is due to this part F, of the flux that the workpiece is pressed against the radial supports 45. Dog 53 is pressed against work 4 by the total magnetic fiux F=F,+F,.

To avoid the force of pressure between dog 53 and workpiece 4 being weakened by the dog attraction to part 49 through the airgap, it is necessary that the area of surface 55 be about 10-15 times that of the front face 56 of dog 53.

Another significant factor in the proposed construction is the correct relationship between the face area of dog 53, on the one hands, and the sum of the areas of surfaces 55 and 56, on the other hand. Calculations and practice have proved that this sum should be about three times greater than the front face area of dog 53.

Dog 53 has a possibility of self-alignment against the face of workpiece 4, since it is connected with the movable part 49 of the magnetic chuck not rigidly, but, for example, by means of an elastic diaphragm 57 allowing limited axial displacement of dig 53, as well as angular deflections by turning about axes passing through the axis of rotation of dog 53.

The embodiment of the arrangement presented in FIG. 9 is mainly intended for internal grinding, for instance, to grind the raceway of the outer race of a ball bearing, locating it from the outer surface 58 on radial supports.

Besides it particular use, this arrangement further differs from the version shown in FIG. 5, by the fact that workpiece 59 is based therein on the axial supports 60 through the outer part of face 61, as in the arrangement according to FIG. 4.

The movable part 62 of the magnetic chuck, which part, as in the arrangement according to FIGS. 7 and 8, performs the functions of the spindle, is mounted by way of bearings 63 in the mandrel stock, and is driven by belt 64 through pulley 65 fixed at the rear end thereof.

Rotation from the movable part 62 of the magnetic chuck is transmitted to dog 66 through two diaphragms 67 allowing self-alignment of dog 66 against the face of workpiece 59. Although in the versions of the proposed arrangement shown in the drawings, the workpiece is presented as a bearing race, the arrangement can as well be employed for high accuracy machining of other articles having a plane location face and a locating surface of rotation.

The choice of the particular embodiment of the proposed arrangement is determined first of all by the shape of the workpiece, and by the type of machining. It should also be borne in mind that besides the embodiments shown in the drawings the proposed arrangement can as well have other modifications representing, for instance, new combinations of the basic elements displayed in the drawings of the embodiments.

Employment of other constructions of magnetic chucks, force elements, etc. is also possible without departing from the concept and scope of the invention, as defined in the following claims.

What we claim is:

1. An arrangement to locate and rotate workpieces with a plane location face and a locating surface of rotation, used mainly for the machining of such workpieces, comprising: two stationary radial supports spaced apart to carry the workpiece surface of rotation; at least one stationary axial abutment determining the position of the workpiece location face; a

drive with a workpiece dog, said dog being capable of selfalignment against the workpiece face; and force elements arranged so as to press the workpiece face to axial abutment with a force smaller than that of said dog pressure against the workpiece.

2. An arrangement according to claim 1, having one stationary axial abutment to support the workpiece opposite the zone of its contact with the working tool, the workpiece dog being linearly movable to permit its self-alignment along the axis of workpiece rotation.

3. An arrangement according to claim 1, having at least three axial abutments to support the workpiece at points not lying in one straight line.

4. An arrangement according to claim 1, wherein the axial abutments are mounted so as to contact the outer zone of the workpiece location surface.

5. An arrangement according to claim 1, wherein the axial abutments are mounted in a fixed mandrel extending along the dog rotation axis.

6. An arrangement according to claim 5, wherein both the axial and the radial supports are mounted on a common bar mandrel.

7. An arrangement according to claim 1, wherein the force elements, which provide for different forces of workpiece interaction with the axial support and the workpiece dog, comprise a magnetic chuck with a magnetic dog capable of selfalignment against the workpiece face.

8. An arrangement according to claim 7, wherein the magnetic dog has two plane parallel faces, one of which, adjacent to the part of the magnetic chuck interacting with the dog, in

its surface area exceeds by an order of magnitude the other face ad acent to the workpiece, which ensures said difference in the pressure forces.

9. An arrangement according to claim 8, wherein the force elements combined with the magnetic chuck providing for magnetic interaction of the dog with the workpiece, comprise spring-type members to press the workpiece mechanically against the axial abutment.

10. An arrangement according to claim 9, wherein said spring-type members are made in the form of an annular elastic diaphragm connecting the dog with the drive. 

1. An arrangement to locate and rotate workpieces with a plane location face and a locating surface of rotation, used mainly for the machining of sUch workpieces, comprising: two stationary radial supports spaced apart to carry the workpiece surface of rotation; at least one stationary axial abutment determining the position of the workpiece location face; a drive with a workpiece dog, said dog being capable of self-alignment against the workpiece face; and force elements arranged so as to press the workpiece face to axial abutment with a force smaller than that of said dog pressure against the workpiece.
 2. An arrangement according to claim 1, having one stationary axial abutment to support the workpiece opposite the zone of its contact with the working tool, the workpiece dog being linearly movable to permit its self-alignment along the axis of workpiece rotation.
 3. An arrangement according to claim 1, having at least three axial abutments to support the workpiece at points not lying in one straight line.
 4. An arrangement according to claim 1, wherein the axial abutments are mounted so as to contact the outer zone of the workpiece location surface.
 5. An arrangement according to claim 1, wherein the axial abutments are mounted in a fixed mandrel extending along the dog rotation axis.
 6. An arrangement according to claim 5, wherein both the axial and the radial supports are mounted on a common bar mandrel.
 7. An arrangement according to claim 1, wherein the force elements, which provide for different forces of workpiece interaction with the axial support and the workpiece dog, comprise a magnetic chuck with a magnetic dog capable of self-alignment against the workpiece face.
 8. An arrangement according to claim 7, wherein the magnetic dog has two plane parallel faces, one of which, adjacent to the part of the magnetic chuck interacting with the dog, in its surface area exceeds by an order of magnitude the other face adjacent to the workpiece, which ensures said difference in the pressure forces.
 9. An arrangement according to claim 8, wherein the force elements combined with the magnetic chuck providing for magnetic interaction of the dog with the workpiece, comprise spring-type members to press the workpiece mechanically against the axial abutment.
 10. An arrangement according to claim 9, wherein said spring-type members are made in the form of an annular elastic diaphragm connecting the dog with the drive. 